As shown in FIG. 1, an exemplary telecommunication system 10 may include mobile units 12, 13, a number of base stations, two of which are shown in FIG. 1 at reference numerals 14 and 16, and a switching station 18 to which each of the base stations 14, 16 may be interfaced. The base stations 14, 16 and the switching station 18 may be collectively referred to as network infrastructure.
During operation, the mobile units 12, 13 exchange voice data or other information with one of the base stations 14, 16, each of which are connected to a conventional land line telephone network. For example, information, such as voice information, transferred from the mobile unit 12 to one of the base stations 14, 16 is coupled from the base station to the telephone network to thereby connect the mobile unit 12 with a land line telephone so that the land line telephone may receive the voice information. Conversely, information, such as voice information may be transferred from a land line telephone to one of the base stations 14, 16, which, in turn, transfers the information to the mobile unit 12.
The mobile units 12, 13 and the base stations 14, 16 may exchange information in either analog or digital format. For the purposes of this description, it is assumed that the mobile unit 12 is a narrowband analog unit and that the mobile unit 13 is a wideband digital unit. Additionally, it is assumed that the base station 14 is a narrowband analog base station that communicates with the mobile unit 12 and that the base station 16 is a wideband digital base station that communicates with the mobile unit 13.
Analog format communication takes place using narrowband 30 kilohertz (KHz) channels. The advanced mobile phone systems (AMPS) is one example of an analog communication system in which the mobile unit 12 communicates with the base station 14 using narrowband channels. Alternatively, the mobile unit 13 communicates with the base stations 16 using a form of digital communications such as, for example, code-division multiple access (CDMA) or time-division multiple access (TDMA). Digital communication takes place using spread spectrum techniques that broadcast signals having wide bandwidths, such as, for example, 1.25 megahertz (MHz) bandwidths.
The switching station 18 is generally responsible for coordinating the activities of the base stations 14, 16 to ensure that the mobile units 12, 13 are constantly in communication with the base station 14, 16 or with some other base stations that are geographically dispersed. For example, the switching station 18 may coordinate communication handoffs of the mobile unit 12 between the base stations 14 and another analog base station as the mobile unit 12 roams between geographical areas that are covered by the two base stations.
One particular problem that may arise in the telecommunication system 10 is when the mobile unit 12 or the base station 14, each of which communicate using narrowband channels, interfere with the ability of the base station 16 to receive and process wideband digital signals from the digital mobile unit 13. In such a situation, the narrowband signal transmitted from the mobile unit 12 or the base station 14 may interfere with the ability of the base station 16 to properly receive wideband communication signals.